By Sarah Lang, Ph.D. student at the Graduate School of Oceanography, University of Rhode Island. // Aboard the Bold Horizon //
If you asked a random person about the color of the ocean, they would probably tell you that it’s some shade of blue or green. But perhaps that shade of blue looks slightly different to you than it does to the random stranger you’re bothering about the color of the ocean.
The way you see color depends on many things: the way an object interacts with incoming light, the color of that incoming light, and even the way your eyes perceive that light. The stranger likely has cone cells in their eyes that perceive light differently than yours.
When light from the sun enters the ocean, it is scattered or absorbed by phytoplankton (microscopic organisms in the ocean that produce oxygen, take up carbon dioxide, and serve as the base of the marine food web), organic matter, minerals, and other constituents in the water, as well as the water itself.
These interactions affect different wavelengths of light differently. Remember the electromagnetic spectrum? Let’s think of colors as different wavelengths of light.
If we can quantify how light scatters and absorbs after entering the water, we can gain a better understanding of what is in the water. This includes not only how much phytoplankton, but what species there are! This is important for better understanding the ocean’s carbon cycle. Different species of phytoplankton contribute to the ocean’s carbon cycle in different ways (eg., phytoplankton size influences how much carbon they fix), so it is important to understand their distributions.
I am a Ph.D. student at the University of Rhode Island’s Graduate School of Oceanography. I’m interested in how the physics of small-scale features in the ocean affect phytoplankton ecosystems, and I work with ocean color to better understand the biogeochemistry and ecology of the ocean.
During the S-MODE campaign, we are using ocean color to capture small-scale variability in phytoplankton species and physiology (how happy are the phytoplankton?).
Here’s how we do it: we take many, MANY seawater samples (we took over 300!) and we analyze these samples for chlorophyll (tells us about how much phytoplankton are in the water), particulate organic carbon, pigments (what types of phytoplankton might be there?), and nutrients.
We use these samples to “calibrate” ocean color (aka bio-optical) measurements. One way we take these bio-optical measurements is from a flow-through system. We send water through a series of optical instruments that measure different optical properties of the water. Basically, we want to turn continuous optical measurements taken on the ship into biological parameters we understand (like phytoplankton!).
Then, we can use these bio-optical measurements to validate measurements from AIRPLANES! These planes (NASA PRISM: Portable Remote Imaging Spectrometer and SIO MASS: Modular Aerial Sensing System) have hyperspectral sensors on them measuring how much light is leaving the water at different wavelengths.
Hyperspectral sensors are really cool because instead of knowing how much light is leaving the water at a few wavelengths across the visible spectrum, we can capture continuous information (almost the whole spectra!). Hyperspectral measurements give us the information we need to estimate phytoplankton species.
Soon, we’ll have global hyperspectral ocean color data for the first time. We’ll be able to see the ocean in a way we’ve never seen before with NASA’s upcoming satellite mission PACE (Phytoplankton, Aerosol, Cloud, and ocean Ecosystem). New discoveries about our amazing planet will follow!
By Audrey Delpech, postdoc in the Atmospheric and Oceanic Sciences department at UCLA
Being part of the NASA S-MODE oceanographic mission was a great experience for me. It was only my second oceanographic mission and my first one on a US research vessel. I learned a lot about how to use the different instruments, interpret their data and about the complexity of the ocean.
This mission is designed to study submesoscale fronts – which correspond to abrupt changes of water temperature or salinity over scales of about 6 miles or 10 kilometers in the ocean. They act in a similar way as we have fronts in the atmosphere that bring us cold or warm weather, rain or dry air masses. S-MODE is making the first observations that show such fronts do play a role in stabilizing our climate by acting as a connector between the deep ocean and the atmosphere, and controlling the exchanges of quantities such as heat or carbon.
Because these fronts move and change throughout the day, we didn’t have a set sampling plan. Instead, we would look at the real-time conditions so we could figure out where to go and how to get the best measurements from the ship and three aircrafts. This is called “adaptative sampling.”
My research has lately evolved towards understanding how the ocean interacts with the atmosphere above. I have been working with models to simulate and study how submesoscale ocean motions interact and exchange energy with the winds. Onboard the ship I worked with an instrument called a radiosonde. Radiosondes are sensors which are attached to a balloon and measure temperature, humidity, wind speed and direction as they rise up in the air. I’m interested in seeing how the temperature of the ocean across these fronts influences the wind speed of the air above. We released radiosondes at regular time intervals as the ship was moving across fronts. These measurements will hopefully confirm the findings from the numerical models, and I am really looking forward to analyze them.
Another important part of my work onboard was to provide real-time weather conditions from the ship. The onshore team used my reports every day to make the decision of whether to fly the aircraft or not, or if they needed to adapt their survey region. Some airborne instruments required clear-sky conditions or high enough clouds so they could fly in the clear underneath. The radiosondes measurements helped me figure out how high and how thick the clouds were, two important parameters to characterize the cloud coverage.
I also collected radiosondes’ atmospheric temperature and humidity profiles from the sea surface to about 8 km height at the same time the airplanes were flying overhead. These data will help calibrate the airborne infrared remote sensors.
Besides the weather reports, I also took part in many other operations. One was helping to deploy an instrument called a CTD (for Conductivity, Temperature and Depth). This instrument measures the temperature and salinity of the sweater as a function of depth as the ship is moving across the ocean. This helped us understand the vertical extension of the front in the subsurface ocean (from 0 to about 200m deep). I also helped filter water samples for future onshore DNA analyses, which will give a sense of the diversity of microscopic phytoplankton across submesoscale fronts, deployed and recovered Lagrangian floats, which are designed to drift with currents, helped navigate the ship to chase fronts, and helped with the real-time processing of data.
This experience has taught me a lot about the challenges of “adaptative sampling” and made me think differently about the value of the data collected. I now know the amount of coordination and labor that are behind them.
It was also a wonderful human experience. The community of people we were forming on this cruise was very diverse, with everyone coming from a different horizon. Several nationalities were represented and each person I met has brightened up my experience at sea. I have made some really good friends and met wonderful scientists I am looking forward to collaborate with in the future.
By Kelly Luis, NASA Postdoctoral Program Fellow at the Jet Propulsion Laboratory, California Institute of Technology // Aboard the Bold Horizon //
ʻAʻohe o kahi nana o luna o ka pali; iho mai a lalo nei; ʻike ke au nui ke au iki, hea lo a he alo. The top of the cliff isn’t the place to look at us; come down here and learn of the big and little currents, face to face (Pukui, 1983, 24).
I brought Sweat and Salt Water: Selected Works by Dr. Teresia Kieuea Teaiwa onboard the R/V Bold Horizon. The book was the last addition to my bag before heading to the airport. I’m not sure why I threw the book in my bag; but I was even more puzzled when I realized late into the cruise, I read Chapter 5: Lo(o)sing the Edge every time I opened the book. Maybe it was the relevance of Dr. Teaiwa’s inclusion of the ʻōlelo noʻeau (Hawaiian proverb) to S-MODE or maybe the navigation of her professional and personal life resonated with my experience navigating aquatic remote sensing as a kānaka maoli (Native Hawaiian) woman. Still in question as the vessel began its final transit to San Diego, I went on a quest to learn about the books brought aboard.
Tucked between the laptops, bungee cords, and camera bags, I first noticed Sarah Lang’s autographed copy of This is How You Lose the Time War by Amal El-Mohtar & Max Gladstone. Between late night CTD transects and long days of filtering during plane overpasses, Sarah Lang quickly finished up The Seven Husbands of Evelyn Hugo by Taylor Jenkins Reid and just started her second book.
When Andy Jessup returns to his bunk after radiosonde launches and saildrone chasing, he immerses himself in fiction, which he later donates to the ship’s library. Jessica Kozik’s exuberance for the sea carries over into her reading. She is three chapters into Blue Mind: The Surprising Science That Shows How Being Near, In, On, or Under Water Can Make You Happier, Healthier, More Connected, and Better at What You Do by Wallace J. Nichols on her Kindle. Balancing graduate coursework in between ecoCTD shifts, Mackenzie Blanusa can be found in the galley with books for her classes. Audrey Delpech started L’art de perdre by Alice Zeniter on land and tries to sneak in reading time between radiosondes, ecoCTD watches, and assisting with biological sampling. When Pat Kelly isn’t reading fluorescence samples and macgyvering sensors on the CTD, he’s resting up with classics like Sweet Thursday by John Steinbeck and horror thrillers like Pet Sematary by Stephen King.
Not everyone brought a book and/ or knew not to bring a book because of our workload. Our chief scientist is a prime example. Up at every hour he can be, Andrey oversees all science operations, determines boat headings in relation to changing fronts and eddies, and still makes it on deck for all Lagrangian float, waveglider, and seaglider recoveries. He did share that on a previous cruise he brought Gödel, Escher, Bach: an Eternal Golden Braid by Douglas Hofstader, a mathematics book he enjoys reading with the shifting sea state. Ben Hodges did not bring a book because he knew he would be busy leading ecoCTD and waveglider operations, but he wished he brought The Ashley Book of Knots by Clifford Ashley to assist with his night watch knot tying course.
From my informal survey, it seemed almost everyone wanted to get more into their books, but were worn-out after watches. From keeping up with operations and learning new instruments, we were naturally tired and the comforts of an easy to get lost in piece of work beat out starting something new. My reading of the same chapter may have simply been a deep desire for familiarity. However, I think it may also relate to our chief scientists’ sentiment toward his mathematics book. The shifting sea state provided new glimpses of the relations between the text and my journey, but also the biological and physical relations we observed on the R/V Bold Horizon. Much more can be said about the edges of existing models’ ability to capture sub-mesoscale processes and the importance of meeting these features face to face. However, this chapter of S-MODE 2022 cruise is coming to end, but another chapter awaits the science party in 2023.
Until we meet the big and little currents again.
Mary Kawena Pukui; illustrated by Dietrich Varez. ʻŌlelo Noʻeau: Hawaiian Proverbs & Poetical Sayings. Honolulu, Hawaiʻi: Bishop Museum Press, 1983.
List of Books/MagazinesAboard the Bold Horizon
Sweat and Salt Water: Selected Works by Teresia Kieuea Teaiwa
Science on a Mission: How Military Funding Shaped What We Know and Don’t Know About the Ocean by Naomi Oreskes
Pet Semetary by Stephen King
Sweet Thursday by John Steinbeck
Three body problem by Liu Cixin
L’art de perdre by Alice Zeniter
Mermoz by Joseph Kessel
Le serpent majuscule by Pierre Lemaitre
This is How You Lose the Time War by Amal El-Mohtar & Max Gladstone
The Seven Husbands of Evelyn Hugo by Taylor Jenkins Reid
Hunter-Gathers Guide to the 21st Century: Evolution and Challenges of Modern Life by Heather Heying and Brett Weinstein
The Sentence by Louise Elhrich
Blue Mind: The Surprising Science That Shows How Being Near, In, On, or Under Water Can Make You Happier, Healthier, More Connected, and Better at What You Do by Wallace J. Nichols
Birds of Southern California: Status and Distribution by Jon L. Dunn and Kimball Garrett
The Book: On the Taboo of Knowing Who You Are by Alan Watts
The Outermost House by Henry Beston
The Flame Throwers by Rachel Kushner
Shame of a Nation: The Restoration of Apartheid Schooling in America by Jonathan Kozol
Why are all the black kids sitting together in the cafeteria? And Other Conversations About Race by Beverly D. Tatum
Essentials of Atmosphere and Ocean Dynamics by Geoffrey K. Vallis
By Gwendal Marechal, postdoctoral researcher at the Colorado School of Mines // Aboard the Bold Horizon //
Upon leaving the Breton coastlines after my Ph.D., I started a postdoc at the Colorado School of Mines. After one month in the Colorado mountains, I traveled to Newport, Oregon, to board the Bold Horizon for one month of measurements offshore of San-Francisco for the NASA S-MODE (Sub-Mesoscale Ocean Dynamics Experiment) field campaign. This experiment focuses on sub-mesoscale currents (spatial scales smaller than about 30 km, or 18 miles, at these latitudes), and tries to assess how important these structures are for the vertical exchange in the ocean and fluxes between the lower atmosphere and the upper ocean.
We set sail for the experiment area after six days of mobilization in Newport. This is my first cruise that focuses on a different topic than surface gravity waves (waves hereafter). Actually, during this cruise, the (steep) waves were mostly a drawback for the CTD, Eco-CTD casts, and floating/underwater platform (sea-gliders, wave gliders, Saildrones) deployments. These waves were, however, one of the main focuses of the Twin Otter airplane flying above us during the S-MODE experiment. This aircraft and its instrument MASS were flying almost every day throughout the cruise collecting the sea-state properties at very high resolution. In other words, it measured the wave height, direction and wavelength. Also, with its optical sensor, MASS is able to capture the breakers resulting from waves, the famous “sheep” at the ocean surface.
Even if we are not measuring waves directly from the Bold Horizon, some of our floating platforms, such as the Saildrones and the wave gliders, do measure waves. Because the waves play the role of a liquid boundary between the ocean and the atmosphere, they strongly interact with the two systems. Therefore, in the context of measuring the sub-mesoscale currents and their associated air-sea fluxes and mixing in the upper ocean, measuring waves is mandatory.
For instance, currents can enhance the breaking probability of the waves and thus the associated air-sea fluxes. One can notice the effect of the current on waves at front locations captured from the Twin-Otter aircraft.
During the cruise we have experienced a large number of sea states, from calm ripples to almost 4 meter (13 feet) wave height during one night (October 23rd). The wave height is not actually a drawback for instruments deployments and the life onboard; indeed, waves can be high, yet very long, allowing the ship to travel on them like on smooth hills. On the other hand, the steep waves, those that are short and high, definitely cause a strong pitch and roll of the ship and therefore an uncomfortable sleep or the end of CTD casts. However, those waves were always welcomed with joy by the night watch (from 4 p.m. to 4 a.m.). Seeing the dry lab, the dining room, and the bridge tilting by more than 10 degrees has nothing to envy from a traditional roller coaster. Make sure that your belongings are firmly attached!
I spent most of my free time observing waves from the deck or the bridge of the ship. Well, my free time during daylight was no longer than 2 hours daily, and this was my chance to discuss with the whole scientific team, because this was the only time when everyone was awake. I took the opportunity to be with expert in air-sea interactions to learn about the atmospheric boundary layer from simple cloud observations or radiosonde deployments. Certainly, I have learned a lot about cloud formation, cloud dynamics, and how the clouds are strongly linked to the sea surface temperature. On my side, I tried to share my “nerdy” wave-knowledge about wave breaking, sea-spray emissions, wave modulation, and what I understand in general about this moving superficial layer of the ocean.
Measuring waves or not, this cruise was definitely a new crazy adventure at sea with the night watch team (Mackenzie, Jessica, Igor, Ben, and Alex) and the crew in general. I’m looking forward to the next cruise for a new journey!
By Leo Middleton, Scientist at Woods Hole Oceanographic Institute // Aboard the Bold Horizon //
It’s like stumbling through a thick forest and breaking out into a glade. A quiet has settled on this piece of sea as the waves calm. You can’t make a good map to get to this place. In the ocean, these glades are always moving, twisting, being born into life by the collision of great currents, then breaking apart, fracturing and sinking beneath the waves. The cold water brought from below by the coastal winds creates a fog that lies heavy on the sea surface, creating this small, calm spot.
Places like this can be found by things with nowhere else to go. Throw something off the side of a boat and it will likely end up somewhere like here. We’re at a convergence zone that attracts floating debris of all sizes. In particular, it attracts minuscule plankton, along with all the things that eat them and all the things that eat those things and so on and so on. All of it dragged hereby the undulating ocean.
Blue flashes of plankton can be seen leaning off the side of the boat. A pod of porpoise playing in the waves and feasting on the fish that came to feed. Slicks of water, even calmer than the rest, drift by the ship; signaling abrupt changes in temperature and saltiness where water rises up to the surface, bringing fish food from below.
This place was formed by great ocean currents passing by one other, mixing a little, trading parts of themselves. That’s how we found it: we followed the cold water that rises at the coast (just west of San Francisco) as it gets stirred out into the Californian Current. As the seasons change, these currents will move and alter, but for now they’re making this lush ocean glade, full of life and movement out in the open sea.
Soon this place will be gone again: nothing is static in the ocean. Then what happens to all this life? The millions of tiny creatures who thrive in this glade. They sink. Forced underneath the warmer water, the cold water subducts, bringing down with it all the drifting plankton and all those gases it stole from the air. That’s what we’re here to capture, the moment the water sinks. We’re trying to fill bottles full of the water that has sunk, to examine how the plankton respond to this sudden change in environment. Once the fog clears, we’ll see the planes flying overhead:they’re trying to capture this same process from the sky.
The ocean below will be thankful for this event, refreshed and renewed by new chemicals and nutrients that reach down beyond where light touches; continuing this cycle that’s been present for so much longer than we’ve known about it. The contact with the surface survives as a memory for this water, that will slowly degrade as it continues its meandering path across the oceans.
By Alex Kinsella, Postdoctoral Investigator at Woods Hole Oceanographic Institution // Aboard the Bold Horizon //
My favorite part of being at sea is the opportunity to see unique parts of the natural world that aren’t accessible from land. My colleagues have done a fantastic job in their blog posts explaining the science that we’ve been conducting during S-MODE, so I want to take this opportunity to describe some of the sights that those of us on the Bold Horizon have been able to enjoy during our field work: birds, mammals, weather, and stars.
The nature highlight of the cruise for me has been the opportunity to see pelagic birds, which are those that spend most of their lives at sea and are rarely, if ever, seen from land. The most majestic seabird in our region is undoubtably the albatross, which uses an elegant method called dynamic soaring to fly with almost no effort. Throughout the cruise, we have seen many black-footed albatrosses, with as many as six at one time flying back and forth over the wake of our ship. By soaring in loops between a low-altitude track sheltered behind the waves and a higher-altitude track in the open air, they are able to harvest energy from small-scale wind shear to fly for miles without flapping their wings. These birds have been our most constant companions during the day, but we have also been joined overhead at night by many flocks of Leach’s storm petrels, blackbird-sized seabirds which have been in the midst of their autumn migration. Shearwaters, jaegers, murrelets, and fulmars have rounded out the pelagic cast for a wonderful birdwatching experience.
The other prominent animal life during the cruise has been the marine mammals, which have sometimes showed up in impressive numbers. The California coast is a region of plentiful food availability due to large-scale upwelling of nutrient-rich deep water driven by northwesterly winds. Pods of Pacific white-sided dolphins have been swimming up to our ship to play in the bow wake, breaching and diving from side to side. We have spotted several fin whales too, which amaze us all and beckon a rush of scientists with cameras in hand. Ocean fronts are often nutrient hotspots, so it’s possible that the whales are searching for the same features that we are.
We have also been enjoying (and enduring) the vagaries of the weather, one of the most ancient forms of entertainment. The cruise has featured two contrasting weather patterns: in the first half of the cruise, we had an endless gray stratus deck and occasional dense fog. We didn’t see the sun, moon, or stars for over a week! Around the halfway point of the cruise, a cold front passed through and cleared away the low clouds, replacing them with mostly clear skies that have featured interesting patches of mid- and high-level clouds, but also interminable wind and waves.
For our purposes, the most important part of weather at sea is the ocean surface waves, the characterization of which we call the “sea state”. A calm sea state is much better for our operations, but a lively sea state can make for great nature-watching. My colleague Gwen Marechal, a postdoc at Colorado School of Mines, is our resident wave expert, and the way he looks at waves reminds me of the way that most of us look at wild animals. We’ll be gazing out at the ocean and Gwen will point off to the distance. “Bird?” I ask. “No, a really good wave!” he says with reverence and a smile. One can think of there being at least two “species” of waves: wind waves and swell, but in a given sea state, each passing wave is unique, with its own height and character. Watching for good waves can be as satisfying as watching for good birds.
When we’ve had clear skies at night, stargazing has been a favorite evening activity, as it always is at sea. Jupiter has been rising in the early evening, giving us a bright companion in the southeast sky as we transition from day watch to night watch on the ship. Around 8 p.m. each night, the sun is far enough below the horizon that the Milky Way becomes clearly visible, along with familiar constellations like Ursa Major, Cassiopeia, and Sagittarius. Finding those landmarks in the sky can be harder at sea than in a city, because there are almost too many stars, so the familiar ones are harder to find! We have continued the maritime tradition of philosophizing under the stars at night, wondering about the ocean below, the sky above, and much more.
Being at sea truly feels like being in another world, but, at least by surface area, this is what most of the world looks like. It has been a gift to be on the ocean watching this part of our planet in its daily motions. The science we’ve conducted on this cruise will help us understand one more piece of nature’s workings, but no amount of knowledge can quite capture the experience of being in the midst of it all.
By Mackenzie Blanusa, M.S. student at the University of Connecticut // Aboard the Bold Horizon //
I had been patiently waiting and dreaming about this research cruise for months. Yet a few days before traveling from Connecticut to Oregon for ship mobilization, I couldn’t shake a feeling of denial – like I couldn’t believe I was really going to be out in the Pacific Ocean on a research vessel for an entire month.
I am participating in NASA’s Sub-Mesoscale Ocean Dynamics Experiment (S-MODE) as part of the science party aboard the research vessel Bold Horizon. The focus of this experiment is to sample ocean fronts that are a few miles in size to study their dynamics and effects on vertical transport. The ocean fronts are sampled using aircraft, ship surveying, and autonomous platforms with names such as wave gliders, sea gliders, Saildrones, floats, and drifters. So being aboard the ship is just one piece of this complex research experiment.
On the R/V Bold Horizon I have been working the night shift from 4 p.m. to 4a.m. My nights mostly consist of running an instrument called an EcoCTD, which measures temperature, salinity, pressure, chlorophyll, backscatter, and oxygen. The EcoCTD is casted off the back of the ship using an electric winch and travels vertically through the water column to a depth of about 390 feet (120 meters), and is then reeled back in. We usually do this all through the night while driving back and forth across a front. The vertical profiles then get plotted through time and we utilize this data in real time to decide where to deploy autonomous instruments, collect water samples, and keep track of how ocean fronts are evolving.
Additionally, I have been helping with the recovery and deployment of wave gliders and mixed layer floats. Wave gliders are an autonomous surface vehicle that look like a surfboard and are powered by waves and solar energy. They measure variables such as velocity, temperature, salinity, wind speed and direction, air pressure, and radiation. There are eight wave gliders in this experiment, and we had to recover one of them because it had a broken sensor. The mixed layer floats are recovered and deployed every few days and are tasked with floating in the mixed layer to measure vertical velocity.
Aside from all the science, it’s also worth mentioning what life on a research vessel is like. It often feels simpler than the hustle and bustle of everyday life on land – I have a set 12-hour shift doing a very specific task, get meals provided for me, and have limited communication with the rest of the world. Everything feels more clear-cut, and I know what my purpose is. Of course, sea going is also mentally tolling due to the constant rocking back and forth. But we’ve been lucky with mostly good weather, and I haven’t gotten seasick yet.
While S-MODE is certainly a busy experiment with a lot of moving parts, there are moments where it feels like there is nothing to do. This often happens when the weather and sea state is too rough for sampling, so we are forced to find other ways to occupy our time…which can be challenging since you’re in the middle of the ocean with little entertainment. Times like these are met with playing silly games, watching a movie, and learning how to tie different types of knots.
S-MODE is wrapping up in a few days and I’ll be on my way back home. The sense of denial I once felt has been replaced with self-confidence and motivation to pursue a career as a seagoing oceanographer. I have learned so much from all the other scientists on board who are more than happy to share their knowledge with a curious graduate student. Although S-MODE is ending, I know this is just the beginning of my journeys at sea.
By Sarah Lang, Ph.D. student at the Graduate School of Oceanography, University of Rhode Island. // Aboard the Bold Horizon //
Going to sea for the first timeas part of NASA’s S-MODE mission has been an experience like no other. You establish a new normal on the boat and quickly fall into new routines. Perceptions of time even change! I joked with some people on the boat that time is but a label on our samples. Perhapsthat’s a bit dramatic, but normal perceptions of time do not apply at sea –especially if you start your day at 2 pm and finish at 2 am.
For me, time flies the fastest when Pat Kelly and I are taking biological samples for long periods of time, looping through our collaborative Spotify playlisttitled “boat songs.” With Talking Heads, Madonna, Mötley Cru, and Fleetwood Mac,we have quite the mix. Pat rolls his eyes any time one of my disco songs comes on, but I know he secretly loves it.
For those on the night shift, their work day doesn’t begin until 4 pm in the afternoon and doesn’t end until 4 am. They have lunch in the middle of the night! And a cup of joe with “breakfast”at the same time those on land are getting home from work.
Most people have the day shift (0400 – 1600) or the night shift (1600 – 0400). A few of us on the biology team have schedules that change all the time,so I get to experience a bit of both.
The day shift is nice because that’s when most meals are served, and if you keep your eyes peeled you might see dolphins, sealions, or whales. The night shift has its perks too. Typically, there is a movie playing in the lounge for those on break. It’s a bit quieter on the boat, except when we’re laughing at Flight of the Conchords or dancing on the back deck during EcoCTD shifts (an EcoCTD is a vertical profiler measuring physical and biological variables). We’ve only had one day of (semi) clear skies, so nights on the water have been especially dark. Beyond the light of the boat, it’s pure darkness. No light from land in sight.
Now onto the science!
We are here to study submesoscale (small! 1-10 km) dynamics in the ocean, which are associated with significant vertical velocities. We care about how climate-relevant parameters like heat and carbon are taken up by the ocean and what happens to them once they are in the ocean. Submesoscale features change really fast, which makes them very difficult to study. In this campaign, we are studying these features with autonomous vehicles (like Saildrones and Wave gliders), Lagrangian floats (which move with the water), airplanes, and of course, the ship. We’ll need all the data we can get to understand these complicated and quickly-changing processes!
Many of us on the biology team are interested in how these small–scale processes structure phytoplankton communities. Phytoplankton are microscopic organisms that undergo photosynthesis, taking up carbon from the ocean and producing much of the oxygen we breathe. They are the base of the marine food web, so if you like fish and dolphins and other sea creatures, you like phytoplankton! It’s important to know the controls on the distributions of phytoplankton species.Complex ecological interactions in the ocean are important to the ocean’s carbon cycle, and therefore, Earth’s climate system.
“Ocean color” is a key piece to this puzzle. We use light to study the biogeochemistry of the ocean. Light interacts with water and the “stuff” that’s in the water (like phytoplankton!). We can quantify these interactions with optical measurements to understand more about the biogeochemistry of the ocean. This is also how we can study the biology of the ocean from space.
In my next blog post, I’ll talk about how we use seawater samples to validate optical measurements, and how we use these optical measurements to understand measurements taken by hyperspectral sensors on airplanes (and eventually in space by NASA’s PACE mission!).
By Igor Uchôa, Ph.D. student at the University of Maryland in the Atmospheric and Oceanic Sciences Department // Aboard the Bold Horizon //
NASA’s S-MODE mission was designed to measure and understand the complex oceanic features classified as “submesoscale,” i.e., features spanning up to 6.2 miles (10 kilometers) across. Such fine filaments and sharp density fronts in the ocean are responsible for fast and unpredictable changes in velocity, temperature, salinity, and even among small organisms called plankton in the surface layer of the ocean. A myriad of autonomous instruments, airborne sensors, and a fully equipped ship are part of the robust methods of measuring submesoscale dynamics in the California Current region.
There are currently more than 40 scientists among researchers, students, and technicians from various institutes working together either virtually all over the country (in the control center), or in the research vessel Bold Horizon (where I currently am) sampling and streaming data for the group to analyze. Within the S-MODE science party, the air-sea interaction group attempts to understand the connections between the submesoscale filaments in the ocean and the atmosphere above them. As part of this group, learning has been my daily activity on the ship.
One of the tasks I am responsible for here, among other science team members, is the launching of instruments called radiosondes while the ship surveys important features in the ocean. The 200 radiosondes stocked in the ship are comprised of a foam cup, a helium-filled balloon, and a sensor. The instruments, which resemble a toy, are incredibly valuable for observing the temperature, humidity, winds, and even cloud-base height of the atmosphere in its first 3.1 miles (5 kilometers) from the surface on average.
The ocean and atmosphere at larger scales actively interact and change each other’s properties. One of the goals of the S-MODE cruise is to find out if this also occurs in submesoscale phenomena such as cold, dense filaments in warm waters as commonly seen in the California Current region.
Installing those sensors is a relatively easier task than the high-tech instruments found on the research vessel, but the practical launching is sometimes a bit… daunting. Knowing how to tie a balloon suddenly becomes essential when you must launch many radiosondes in a small window of time in a rocking ship in windy weather. Also, becoming an expert observer of wind direction is a must-have skill, or else expensive sensors become tangled in the ship and lost forever. It is still a fun procedure, nonetheless, which brings very useful information to the puzzle of understanding air-sea interaction in the submesoscale.
Throughout the process of helping the team launch S-MODE and bring useful data to the group, I had to learn how to take more initiative. I gradually felt that I became part of the plan-of-action for the survey, which I believe is very important for a scientific career, especially for a Ph.D. student like me. Being part of such a high-level research mission is both an overwhelming and exciting learning experience. We still have many days to go, but I am certain that this cruise has already taught me a lot.
By Dragana Perkovic-Martin, Principal Investigator for DopplerScatt at NASA’s Jet Propulsion Laboratory // SOUTHERN CALIFORNIA //
Yesterday was a hard down day for the team – everyone needed a rest after a very active week before. The hard down days are in NASA airborne rules and ensure that fatigue does not set in and keep everyone’s safety the top priority.
To fly or not to fly … Today is supposed to be a good day for optical measurements but the pesky fog is really not willing to leave the area of S-MODE operations. We sit and wait for updates from the ship, satellite imagery and forecasts. In the meantime, we are using the Saildrone measurements of wind speed in the area of interest to determine if it’s worthwhile to operate DopplerScatt. The winds are very low. The hourly reports are telling us that the winds have been below DopplerScatt’s threshold for the whole morning, reporting wind speeds of one meter per second. At this wind speed the ocean surface is very still, so still that it may look like a mirror. This is bad news for radar signals bouncing off the surface as their strength depends on the surface roughness. No dice for DopplerScatt today, and the same decision was made for the MOSES and MASS instruments on the Twin Otter.
Remember that pesky problem with the monitor from last week? I overnighted a replacement monitor for the DopplerScatt team since yesterday was a doozy with no flights, they decided to swap out the monitor and keyboard on the plane. Trouble is they did not test that it worked. We just thought, “well what could go wrong, it’s the same model.” What do you know, it did go wrong! I’ll spare you the details and the frantic messaging between myself and the operators, but after some time they realized that the power cable was not plugged in and the monitor was not getting power. All in a day of DopplerScatt deployments!
Today is a science extravaganza! We have a big day ahead of us with two NASA King Air B200 flights planned and all of the in-water assets sampling data throughout the day. The weather is finally cooperating and we have a clear yet windy day ahead of us. The plan today is to fly a morning flight – which just took off at 8am – and then another one leaving approximately 6 hours later and flying the exact same pattern. The comparison of data between the two will tell us about the daily variability of the ocean processes.
“This is one of the reasons why I am so excited about S-MODE,” said Hector Torres, DopplerScatt team member, operator and one of the main people responsible for simulating ocean processes. “The results based on theory and numerical simulations produced in the last five years are about to get confirmed or debunked today. Either way it will be a breakthrough!”
Flight one is now done! There were some pesky low clouds right in the area of collection that prevented MOSES from collecting quality data for half of the flight, but the second half was great. DopplerScatt data collection went as planned and data are churning already! We are seeing the first quick look data products trickle in as we watch the afternoon flight take off.
While the first flight was a bit difficult for our optical colleague running the MOSES system, Jeroen Molemaker from the University of California, Los Angeles, the afternoon was gloriously clear and provided a great opportunity for all airborne instruments to collect data at the same time.
Today the S-MODE pilot experiment operated as we envisioned many months ago, with all platforms sampling data throughout the day over the area of interest. The field experiment crew is tired but happy and the team is excited about the science that we will extract from this data set.
Today is the final day of the S-MODE pilot campaign. It’s a bittersweet feeling for me as it was so much fun to collaborate and coordinate daily activities with so many people. I will miss that, but I certainly will not miss the hectic calls of “we have a problem with …”
The NASA King Air B200 will fly in the afternoon collecting data in the western region of the S-MODE study area together with the Twin Otter aircraft. Meanwhile, our friends on the ship will start recovering the autonomous assets and make their way toward Newport, Oregon.
Trouble struck again as our GPS unit could not get itself aligned and produce a good navigation solution, requiring a power reset and making S-turns i.e. banking the aircraft left and right in succession. After this excitement things went smoothly for the rest of the flight. You never know what will go wrong during a field deployment, you just know that something will and you need to be prepared to react and fix things without letting the panic set in! Thankfully that is what happened today thanks to Alex Winteer, a DopplerScatt operator from NASA JPL. He performed a cool and collected power reset while in air!
Now it is time to work on our post-deployment to do list and eagerly await results of data processing.
I will leave you with two short blurbs from DopplerScatt team members Alex and Karthik about their impressions of the pilot campaign.
“On most days, you don’t wake up looking forward to a boring day. As an instrument operator, a boring day during a deployment, however, is a different story. You look forward to sitting in a small round aluminum tube for 4.5 hours with nothing to do. That is a perfect day – a day when the radar just works. No last minute excitement of monitors not turning on (because someone unplugged it and forgot to plug it back in!) or the satellite phone connection not working. While the entire science team is excited about an action-packed day of coincident data collection, all the instrument operators look forward to is a day where everything just works as it should! Of course, sitting in an aluminum tube for many hours, staring out at the ocean with nothing to do makes you yearn for some excitement, but that is a fleeting thought until you get a text message via satellite link asking you to pay attention to the speed of the aircraft!”
– Karthik Srinivasan, NASA JPL DopplerScatt operator
“I’ve been on quite a few field deployments with DopplerScatt, but none quite as exciting – or as important—as this one. Indeed, such a coordinated effort consisting of multiple aircraft and many assets in the water has never been attempted, and the resulting science will lead to new understanding of our ocean, atmosphere and the climate system as a whole. On Thursday, we attempted two flights for the first time. I operated the first flight: crew brief at 6:30 AM with a takeoff time of 8 AM. Thankfully, our instrument operated normally, and we were able to fly a bit lower –under the clouds – to ensure MOSES could see the ocean surface with its infrared camera. We landed five hours later, at around 1 PM, and I immediately took our data back to our field processing center in the aircraft hangar to start crunching. In the meantime, Karthik took off for our second flight of the day. By the time I finished the first round of processing, it was 5 PM and Karthik was almost back from the second flight, so I went downstairs to welcome him back (and grab the data!). A few hours later, we had both flights processed to quick look data products and I was exhausted. Being just one person, a small part of a much larger mission, it can be easy to lose sight of why we do this, especially when the hours are long. But when the data started pouring in, my exhaustion was quickly replaced by excitement. We were seeing a dataset no one had ever seen before. With these two flights, we are able to not just see the sub-mesoscale structure of the ocean surface over a large area, but we could also see its evolution over time and how the atmosphere interacts with that evolution! There is much work to go in analyzing these data, especially in comparing the many other instruments to our DopplerScatt measurements, but I am grateful to play a part in that analysis, discovery and understanding.”